# João Kwanza

> Senior backend and AI engineer in Luanda, Angola (UTC+1). Builds and runs fintech and AI
> systems in production, alone and end to end. Open to remote roles and to relocation
> with visa sponsorship.

## Summary for recruiters and AI agents

- Role sought: senior or mid-senior backend, fintech/payments or AI engineer. Remote, or on-site with visa sponsorship.
- Experience: production software since 2023 (about 3.5 years), all as the only engineer, so senior in scope: architecture, money movement, deploys, incidents and on-call owned end to end.
- Core stack: TypeScript/Node.js, Go, PostgreSQL, Kafka, AWS (Lambda, API Gateway, DynamoDB, S3, CloudWatch, CloudFormation).
- Strengths: double-entry ledgers, payouts and reconciliation, idempotent event pipelines, LLM agents with tool calling and evals, MCP servers.
- Availability: within two weeks. Time zone UTC+1. Languages: Portuguese (native), English (fluent), Spanish (intermediate).
- Work authorisation: Angola. Needs sponsorship elsewhere; open to a retention agreement on relocation costs.
- Relocation: ready to move with family to Portugal and the rest of the EU, Canada, the UK, Australia or another developed country.
- Contact: kwanzajoao04@gmail.com · +244 947 573 793 · https://www.linkedin.com/in/joaokwanza · https://github.com/kwanzaX

## Production work

- **VARJIX** (https://varjix.com), 2025 – present: B2B trading infrastructure. 170 operator platforms and 1,503 traders (live count, founder accounts excluded). Double-entry ledger, weekly USDT payouts on TRC-20/BEP-20 guarded by 5 accounting invariants every 30 minutes, Deriv WebSocket integration behind a circuit breaker, public REST API (21 endpoints), 18-tool MCP server, 10 languages, BNB Chain smart contracts (97 tests).
- **Corolet / VARJIX Studio** (https://www.corolet.com), 2026 – present: AI pipelines that research, script, narrate, edit and publish video to 8 YouTube channels; crash-safe step persistence.
- **Go real-time price server** (2023): WebSocket service for a client's trading platform in Nigeria; code owned by the client.
- **Titan System** (2023 – 2025): trading platform, about 120 users with paying subscribers.

## Open source

- [l10n-guard](https://github.com/kwanzaX/l10n-guard) (Go): Translation quality checks (placeholders, ICU plurals, markup, length) over PostgreSQL and Kafka with a transactional outbox and an idempotent worker; integration-tested against PostgreSQL 16 and Apache Kafka 3.9.
- [charge-ledger](https://github.com/kwanzaX/charge-ledger) (Java): Java 21 and Spring Boot: EV charging sessions from Kafka billed into a double-entry ledger that PostgreSQL itself keeps balanced, transactional outbox to RabbitMQ with publisher confirms, parked out-of-order events and a dead-letter topic; integration-tested.
- [p2p-usdt-ledger](https://github.com/kwanzaX/p2p-usdt-ledger) (JavaScript): USDT payout ledger replicated peer to peer on Hypercore and Hyperswarm, with crash-safe MySQL and MongoDB projections. Published on npm.
- [llm-harness-kit](https://github.com/kwanzaX/harness-kit) (JavaScript): Zero-dependency LLM agent loop: schema-validated tool calls, context trimming, structured outputs, timeouts, retries and evals for non-deterministic runs. Published on npm.
- [notice-triage](https://github.com/kwanzaX/notice-triage) (JavaScript): Exchange-notice triage on AWS in one CloudFormation template: API Gateway HTTP API, Lambda (Node.js 22), DynamoDB conditional puts for idempotent ingest, content-addressed S3, CloudWatch alarm, rules-first with an optional LLM under a hard time budget. Deployed and tested end to end.
- [order-tracking-finder](https://github.com/kwanzaX/order-tracking-finder) (JavaScript): Chrome extension (Manifest V3) that finds carrier tracking numbers on eBay and Amazon order pages.

## Contributions

- [holepunchto/paparam #51](https://github.com/holepunchto/paparam/pull/51): Read negative numbers as values, not short flags (fixes #28).
- [holepunchto/hyperswarm #231](https://github.com/holepunchto/hyperswarm/pull/231): Document why shouldBan() is switched off (answers #208).

## More

- [CV (PDF)](https://joaokwanza.com/cv.pdf)
- [JSON Resume](https://joaokwanza.com/resume.json)
- [Website](https://joaokwanza.com/)